People tend to wear heavy clothes to keep warm in winter, but wearing heavy clothes could make people feel uncomfortable. Further, heavy clothing storage would result in much inconvenience. Therefore, manufacturers have developed such heat preservation articles as hand warmer packs, etc. to provide heat. However, these articles can merely retain heat in certain body parts apart from inability to control the temperature. Moreover, they can also be used over a very short time period, thereby making them inadequate to provide heat retention efficiency people need.